Safety device for printing machines



' April 17, 1928.

1,666,584 1,. P. SCHINDLER SAFETY DEVICE FOR PRINTING MACHINES FiledSent. 2. 1924 Fatented Apr. 17,1928.

LINUS PAUL SCHINDLER, OF HAMBURG, GERMANY.

SAFETY DEVICE FOR ERINTING MACHINES.

Application filed September 2, 1924, Serial No. 735,504, and in GermanyAugust 23, 1923 This invention has for its object to improve theconstruction 01 the commonly used safety devices designed to prevent, inprinting presses, the hand of the workman getting injured by gettingbetween the printing cylinders. With this object in view a specialpositive connection is arranged between a guard'of roller blind form andthe device for starting or stopping the printing press. This connectionis constructed so that the printing press cannot be started unless theguard has been pulled down completely.

Another obj ectof the invention is the provision of means on saidconnection for pre- 9- venting the printing cylinders jumping out oftheir position in the machine frame when said bearings should not havebeen properly fixed before the machine is started.

An embodiment of the invention is shown by way of example on theaccompanying drawing which illustrates the safety device mounted on afly printing press of known construction.

Fig. 1 shows the corresponding parts of 4, the printing machine in sideelevation.

Fig. 2 shows in plan view the pull rod with two pro ections and thecorresponding bearings of the printing cylinders.

Fig. 3 shows on larger scale in side elevation, the .outer side wallbeing removed, one of the curved guides for the guard.

Fig. 4 shows in plan view partly in section a portion of one of thecurved guides with a portion of the guard.

Fig. 5 shows in section the crank and the ratchet mechanism.

On the side walls 1 of the front part of the machine frame two curvedguides 2 of channel-shaped cross section are fixed which terminate eachat the rear end in a boxshaped casing 3. A cross-axle 4 is journaled inthe upper ends of the guides'2 and serves for winding up the guard 5similar to a roller blind which is made from canvas,

, wire gauze or other convenient material.

The lower end of this guard 5 is attached to a cross rod 6 on each endoi? which a slide or carriage is fixed, said two carriages 7 beingguided in the channel-shaped curved guides 2. The two slides orcarriages have each two rollers 8 rolling on the upper and lower membersof the corresponding channel-shaped guides. The guard 5 is wound up onthe axle 4 through the action of a spring 9. In each casing 3 of theguides 2 two looking pawls 12, 13 are pivotally mounted on a shaft 10and a ratchet wheel 14 is further mounted on a shaft 11 extending acrossthe machine frame. 011 one end of said shaft 11 projecting from one ofthe casings 3 a crank is keyed which, through a rod 16, is connectedwith the starting lever 17 of the print-ingpress. The locking pawl 12engaging with the ratchet wheel 14 prevents shaft 11 from rotating andconsequently the operation of the starting lever 17 so that in this casethe starting lever 17 cannot be operated. Only when the guard 5 has beenpulled down and the noses 18 of the carriages 7 have penetrated into thecasings 3 the locl'ring pawl 12 is raised and brought out of engagementwith the ratchet wheel so that the shaft 11 is liberated and can berevolved. The carriages or slides 7 are locked in their position each bymeans of a hook 19 which grips over the cross rod 6. hen the machine isnow started by means of the starting lever, 17 the second pawl 13 israised through the intermediary of an eccentric disk 20 keyed on shaft11 of the ratchet wheels so that the corresponding hook 21 of pawl 13grips behind the stud 22 ot the nose 18 of the carriages or slides 7.The carriages 7 are thus securely held duringthe working of the machineeven when the hooks 19 are released or if they should he accidentallyreleased. When the machine has been stopped the pawls 13 release theslides or carriages 7 so that on the releasing of hook 19, the guard 5is pulled up or wound up through the action of spring 9.

The printing cylinders not shown in the drawingare removably mounted inthe printing press. To remove the printing cylinders their bearings 24,which are diagrammatically shown in the Figs. 1 and 2, or the coverplates of these hearings, must be removed. These bearings 24 or theircover plates are fixed by means of screws. The axles of the printingcylinders are journaled in said bearings 24. If the workman should, forinstance, forget to fix the screws for the cover plates of the bearings24 after a fresh printing cylinder has been inserted, the printingcylinder might be thrown out of its bearing 24. In order to prevent thisthe connecting rod 16 has two projections 25, which, when the startinglever has been brought into the position for starting the machine bearagainst the bearings 24 and serve as substitutes for the screws insecurely holding the bearings 24 in their position.

The printing cylinders are further held by downwardly projecting arms 23of the cross rod 6. \Vhen the machine is at rest, owing to the shiftingof rod 16 as shown in Fig. 2, the bearings are released by theprojections 25 and may be removed. The revolving guard is forced bytransverse rods 26 to adapt itself to the curvature of the guides 2 whenit is being stretched. For the spring 9a coi nterweigdit'might besubstituted. It instead of the starting lever 17 the machine has anyother starting means the pull rod 16 mustbe connected with the same in aconvenient manner so that the crank is operated when the machine isbeing started.

A safety device for printing machines comprising in combination with thestarting lever of the machine, a guard or roller blind on a revolvableaxle to which one end of said guard is attached, a cross rod in the freeend of said guard, two carriages one at either end of said cross rod,two curved channel shaped guides on the machine frame in which saidcarriages are guided, a casing at the lower end of said two curvedguides, an aXle r'iurnaled in each of said casings, ratchet wheels onein each casing keyed on said aXle a spring controlled locking pawlpivotally mounted in each casingso that it is adapted to engage with andlock the corresponding ratchet wheel, a nose on each carriage adapted topenetrate into the corresponding case ing when the guard has been pulleddown so that said nose disengages said pawl from the correspondingratchet wheel, a crank arm on one end of said axle, a rod connectsaidcrank with said starting lever of the machine so that theoperation saidstarting lever is possible only when the pawl has been operated by thepulled down guard, and means for locking the corresponding carriageof'said guard during the working of the printing machine.

In testimony whereof I afiix my signature.

LrNUs PAUL SGHINDLER.

